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Master's Dissertation
DOI
10.11606/D.76.2002.tde-09042008-091650
Document
Author
Full name
Helena Carolina Braga
E-mail
Institute/School/College
Knowledge Area
Date of Defense
Published
São Carlos, 2002
Supervisor
Committee
Napolitano, Reginaldo de Jesus (President)
Bernardes, Esmerindo de Sousa
Moussa, Miled Hassan Youssef
Title in Portuguese
O operador de Wigner aplicado a colisões de mudança de estrutura fina entre átomos alcalinos no regime frio
Keywords in Portuguese
Colisões de mudança de estrutura fina
Colisões frias medidas por fótons
Física atômica e molecular
Operador de Wigner
Processo de perdas em armadilhas magneto-ópticas
Abstract in Portuguese
Neste trabalho abordamos os processos de perdas colisionais por mudança de estrutura fina e por escape radiativo. Estes processos são importantes por serem os principais fatores limitantes da densidade e da permanência de átomos confinados em armadilhas magneto-ópticas. A utilização do formalismo de Wigner nos possibilitou tratar a dinâmica dos graus de liberdade internos do sistema de forma puramente quântica, enquanto tratamos os graus de liberdade translacionais de maneira semiclássica. Com este formalismo deduzimos equações inéditas para uma colisão unidimensional e desenvolvemos um algoritmo, também inédito, para a resolução numérica de tais equações.
Title in English
The Wigner operator applied to fine-structure collisions between alkaline cold atoms
Keywords in English
Atomic and molecular physics
Cold colisions
Fine structure changing collisions
Loss processes in magneto optical traps
Wigner operator
Abstract in English
In this work we study the collision loss processes caused by fine-structure change and radiative escape. These processes are important because they limit the density and the confinement time of atoms in magneto-optical traps. The use of the Wigner-function formalism allows us to treat the internal degrees of freedom purely quantum mechanically, while treating the dynamics of the external degrees of freedom quasi-classically. This dissertation employs this formalism to derive for the first time, quasi-classical equations describing one-dimensional cold collisions, including dissipation due to spontaneous emission, and an algorithm, also for the first time, to solve numerically the mentioned set of coupled equations.
 
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HelenaBraga_M.pdf (2.18 Mbytes)
Publishing Date
2008-04-15
 
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